Tunze Osmomot 5024 Water Level Controller & Calcium Dispenser
Evaporation is a big deal to me. Skimmers work better, corals seems happier and less algae occurs if you maintain a constant water level.
So I have been pretty stressed out with my sumpless tank I have now. The I.V. I was using was a constant catch up / slow down scenario punctuated with hair-raising kalk bombs that were released in the tank. I.V.s aren't great for dosing powder additives - go figure!
So I bit the big one and layed down the bucks for a Tunze Osmomot and their optional calcium dispenser.
Osmomot on right side of tank (brown box) and black controller on wall.
The way the Osmomot works is pretty wild. You know how a wet/dry or a sump works right? As water evaporates, the water level goes down in the sump.
Well the Osmomot works the same way. The box sits in the tank, drawing water in from the top and pumping it slowly out the bottom with a 70 GPH pump. As water evaporates, the water level goes down in the box and exposes an infra-red sensor inside. When exposed, the water pump sitting in a bucket, pumps freshwater back in until the sensor is submerged again!
The osmomot is very accurate. Tunze claims it can detect a 1/10 mm drop in water level! My experience is a little bigger than that but still very good. More like a couple MMs. This is still highly satisfactory and much better than most electric switchs that drop a full inch before activating. My experience is probably due to the fact that my tank isn't perfectly level on this old wood floor and the fact that I have a surge device going on my TetraTec filter. Yet it still works very well inspite of this. The Osmomot also has a high level sensor and audible alarm for safety.
The whole setup runs on just 9 volts of electricity! The a/c adapter can be kicked up to 12 volts if you keep the pump far away and need more power. My works fine at 9v and is very quiet.
The calcium dispenser shown here inside the bucket of freshwater was a great option. As mentioned above, I had serious problems trying to dose with an I.V. Well the dispenser is simple, effective and clean. Simply fill to a little above the neck with water, add a teaspoon of kalk, put the cap back on and shake for a few seconds then slip it back on the holding rail. Water comes in from the pump at the bottom and goes out the top. Being first in the chain, the pump never gets exposed to kalk, extending it's life. A check valve prevents back flow to the pump.
It's so easy and mixes the kalk really well for the top off water - it doesn't shoot a lot of unmixed kalk directly in the tank. I am really pleased with this dispenser.
Conclusion
My only grief with this setup was due to a serious omission in the instructions. It did not indicate how the pump and sponge were to sit in the Osmomot box. Of course, I put it in wrong initially.
I figured out it went in sideways, but I put it in with the top of the pump facing the side wall thinking it was farther from the sensor this way. However I found out after much drama that it didn't sit low enough and as a result the water level in the box would not go low enough to expose the sensor. As a result, water was not replaced and the pumped air in the tank all day while I was at work!
Roger at Tunze was extremely helpful and we figured out I had the pump in wrong. Once I had it in right (intake facing side wall with sponge in between), those problems went away.
Another problem was that the new sensor trapped air initially causing overfills. I used my fingers to remedy, but later Roger told me to rinse with hot water and a little mild detergent. Wasn't necessary by then, but did it anyway. No more problems there. Probably have to do it once in a blue moon to remove kalk deposits, etc..
By far the worst problem encountered was assembling and installing the mount for the Osmomot. They are designed for trimless European tanks!!! The gap caused by the trim on American tanks was a nightmare to overcome. Eventually I added a 4 suction cup plate from a RIO pump to fill the gap and this has worked very well. Yet fiddling with this took me a couple days of thought and stress!! Roger said there is a holding set for it and would send me one. I look forward to checking it out.
The Osmomot is designed for sumpless tanks but could be mounted in a sump on a baffle. There is also a version made for sumps called the Universal.
Overall I am very pleased with this setup now that it is installed and properly set up. It is extremely accurate. If you are sick of the drama caused by evaporation and dosing, the close to $300 for this setup may be worth the piece of mind.
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matt
Tunze Osmomot 5024 Water Level Controller 
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I think you need nother starter clam 
Call me! 
